"The music part just took so much discipline, it was physical to get the voice strong, to get the fingers strong for playing guitar. It was super hard work," said Oscar-winning actress.
"But psychologically I had a really hard time understanding addiction, how someone could be that self destructive."
Paltrow had some all-star help when it came to perfecting the art of being a music superstar. She says she leaned on a few of her famous friends for inspiration.
"It wasn't just like playing a singer, it was like a super, super huge star, so I thought, how am I going to pull this off? And what is it about Beyonce, for example, that makes her such a massive global star? And it's that incredible confidence, she has the most amazing confidence. So I thought, if I can just get a little bit of that I'll be OK," said Paltrow.
"Country Strong" marks Paltrow's first lead role in almost seven years. She's let her career take a backseat to her real life role of mom.
While her character in the movie seems to have a tough time balancing things, Paltrow says after 20 years in the business she's learned how to keep a passion for work without letting it completely overtake her world.
"Of course there are days where it just feels like a job, especially when you're on something you don't believe in, you don't really like it or you think it's going to turn out badly, and it usually does when you feel that way," Paltrow said.
"But you have to take the rough with the smooth. And it's such a fantastic job and I'm so lucky that I've been able to do it and had some success doing it."
"Country Strong" opens in wide release nationwide on Friday, Jan.7. The film, rated PG-13, also stars Tim McGraw, Garrett Hedlund, and Leighton Meester.